Jellyfish force nuclear plant shutdown

Operators of the Swedish Oskarshamn nuclear plant were forced to close one of the plant’s reactors due to an enormous cluster of jelly fish clogging the pipes of the cooling system.

The plant’s personnel were working hard throughout Tuesday to clean tonnes of jellyfish from the pipes that suck in water from the sea. Later on the day, engineers at the plant started with preparations to reboot the reactor.

Constant supply of water is necessary for the functioning of nuclear power plants to cool their reactors and turbine systems, which is why many such plants are built near large bodies of water.

The Oskharshamn power plant, with its 1,400 megawatts of output, is the largest boiling-water reactor in the world. It features the same technology as the crippled Japan's Fukushima Daiichi power plant.

It has not been the first case of jellyfish causing problems to nuclear power plants. Last year, California's Diablo Canyon facility had to shut its reactor after gobs of sea salp - a gelatinous, jellyfish-like organism - clogged its intake pipes. In 2005, the first unit at Oskarshamn was temporarily turned off due to a sudden jellyfish influx.

According to marine biologists, such events could become more frequent in the future as the warming climate favours jellyfish proliferation.

"It's true that there seems to be more and more of these extreme cases of blooming jellyfish," said Lene Moller, a researcher at the Swedish Institute for the Marine Environment. "But it's very difficult to say if there are more jellyfish, because there is no historical data."

The species that caused the Oskarshamn shutdown is known as the common moon jellyfish